JPH10257262A - Flat bed original reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold the light reception quantity of a CCD to be constant even if various transmissive originals different in thickness are read or even if distortion occurs in an original cover by setting a distance between the transmissive original loaded on the original stand of an original reader and a light source with the thickness of the transmissive original as a reference. SOLUTION: The distance between the transmissive original 1 loaded on the original stand 11 and the light source 3 is variably set in accordance with the thickness of the transmissive original 1. A diffusion board 5 can be moved in the direction of the light source 3. The diffusion board 5 is engaged with a cover frame 13 by a clearance part 20 formed of the cover frame 13 of the original cover 2 and the diffusion board 5. Light quantity illuminated on the transmissive original 1 is stabilized, the light reception quantity of CCD is also stabilized and is kept to be constant. The diffusion board 5 holds the distance between the transmissive original and the light source to be constant by tracing the transmissive original by gravity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flatbed type document reading apparatus capable of reading a transparent document.

[0002]

2. Description of the Related Art FIG. 6 is a schematic view of a prior art. In FIG. 1, a flat-bed type document reading apparatus capable of reading a transparent document 1 includes an apparatus main body 60 and an openable and closable document cover 52 attached to the apparatus main body.

The apparatus main body 60 includes a reading unit 62 having a reflecting mirror 63, an imaging lens 64, and a CCD 65, and runs on a reference axis 66 in the sub-scanning direction by driving a drive belt (not shown). The apparatus main body 60 also includes a document table 61 on which the transparent document 1 is placed.

On the other hand, the original cover 52 is configured so that a light source unit 54 having a light source 53 is driven by a driving element (not shown) in synchronization with the movement of the reading unit 62. Further, the document cover 52 is provided with a diffusion plate 55 facing the document table 61 in order to diffuse the light of the light source 53 and absorb the positional deviation from the reflection mirror 63.

When reading the transparent document 1, the transparent document 1 is placed on a document table 61 and the document cover 52 is closed. afterwards,
The light of the light source 53 is applied to the transmissive original 1, and is transmitted through the original table 61 through the reflecting mirror 63 and the imaging lens 64 to the CCD 6.
5 and converted into image data.

FIG. 7 is a structural view of the prior art. FIG. 3 shows a detailed structure of the document cover 52. As a driving element of the light source unit 54, the document cover 52 includes a guide rail 80 extending in the sub-scanning direction.
A rack 81 is formed on one of the zeros. The unit frame 79 of the light source unit 54 has the light source 53, a pulse motor 87, and gears 83 and 84. Further, it has a pinion 82 and is axially mounted so as to mesh with the rack 81. The pinion 82 has a pulse motor 87 and a gear 8
Driven via 3,84.

A slide shoe 85 provided on the light source unit 54 is resiliently pressed by a pressing element 86 on the surface of the guide rail 80 opposite to the surface on which the rack is formed, at positions on both sides of the rack engagement position. Light source unit 54
Is defined by these two slide shoes 85.

Further, on both sides of the unit frame 79 of the light source unit 54, there are provided contact members 78 made of, for example, sliding members, which are in contact with the document cover 52. One of the contact members 78 presses the cover frame 56 of the document cover via a pressing element 86. This light source unit 5
Reference numeral 4 denotes a vehicle that runs with reference to the cover frame 56 of the document cover 52.

The diffusion plate 55 is fixed to the cover frame 56 with screws or the like.

[0010] On the other hand, the form of the transparent original 1 read by the flatbed type original reading apparatus is a single film 1a as shown in FIG. 8 (a) or a film 1a as shown in FIG. 8 (b). Some are stored in the folder 1b or the case 1b. The thickness of the film 1a alone is about 0.2 to 0.3 mm.
The thickness of b is about 2 to 3 mm.

When the transparent document 1 is placed on the document table 61 and the transparent document 1 is thick, the document cover 52
May not be closed to a predetermined position. Also, depending on the accuracy of the document cover mounting portion, in the case of a thin document, the mounting portion side may float with respect to the document. In these cases, the distance between the light source 53 and the transparent original 1 varies with respect to the main scanning direction. FIG.
As shown in (a), even when the original cover 52 is distorted in the Z direction, the distance between the light source 53 and the transparent original 1 varies. For this reason, it becomes difficult to keep the amount of light received by the CCD constant.

As described above, in order to read a transparent original while moving the light source 53, in order to keep the amount of light received by the CCD constant, the accuracy of mounting the original cover and the accuracy of the light source operation unit are required.

[0013]

As described above, the flatbed type document reading apparatus according to the prior art which can read a transparent document has the following problems.

1) When reading various types of transparent originals having different thicknesses or when the original cover is distorted, the distance between the light source and the transparent original varies, and the
The light receiving amount of D cannot be kept constant.

2) The accuracy of mounting the document cover and the accuracy of the light source operation unit are required.

3) As described above, it is impossible to realize a stable and stable image with an inexpensive mechanism.

[0017]

In order to solve the above problems, the present invention takes the following measures.

In a flat bed type document reading apparatus for reading a transparent document, the distance between the transparent document placed on the document table and the light source is set based on the transparent document.

By taking the above measures, the distance between the light source and the transparent original is always kept constant even when various kinds of transparent originals having different thicknesses are read or when the original cover is distorted. Therefore, it works to keep the amount of light received by the CCD constant.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention adopts the following embodiments.

As shown in FIG. 1, in a flat-bed type document reading apparatus comprising a device body having a reading unit and a document table, and a document cover having a light source and a diffusion plate and openably and closably mounted on the device body, The distance between the transparent document 1 placed on the document table and the light source 3 can be changed according to the thickness of the transparent document 1.

Further, it is preferable that the diffusion plate 5 can be moved in the direction of the light source 3.

Further, the diffusion plate 5 is provided with a gap 20 formed by the cover frame 13 of the document cover 2 and the diffusion plate 5.
It is also preferable to hold the cover frame 13 with the cover frame 13.

It is also effective to provide the document cover 2 with a pressing element 6 for pressing the diffusion plate 5 toward the document table 11.

It is also preferable that the light source unit 4 having the light source 3 travels in contact with the diffusion plate 5.

Further, it is preferable to provide contact members 14 for contacting the diffusion plate 5 at both ends of the light source unit 4 in the main scanning direction.

It is also effective that the light source unit 4 includes a pressing element 12 composed of a spring 15 for pressing the diffusion plate 5.

Further, as shown in FIG. 5, the light source unit 24 includes a pressing element 42 for pressing between the cover frame 13 and the light source unit 24 by a spring 43 having a contact member 41 at a substantially central portion in the main scanning direction. It is also desirable to provide.

By taking the above-described embodiment, the following operation works.

Since the light source is arranged with reference to the transmissive document placed on the document table, the amount of light applied to the transmissive document is stabilized, so that the amount of light received by the CCD is also stably kept constant.

Further, the diffusion plate traces the transparent original by its own weight, thereby keeping the distance between the various transparent originals and the light source constant.

Further, the diffusion plate traces the transparent original by the external pressure, and keeps the distance between the various transparent originals and the light source constant by the external pressure even if a warp exceeding the weight of the diffusion plate occurs.

Further, by driving the light source unit having the light source in contact with the diffusion plate, the light source unit can be driven with the diffusion plate as a reference. Therefore, by stabilizing the amount of light applied to the transmission original, the amount of light received by the CCD is also stably maintained at a constant level.

Further, the light source unit can be driven with reference to the diffusion plate. At the same time, the diffusion plate traces the transparent original by the external pressure, and keeps the distance between the various transparent originals and the light source constant by the external pressure even if a warp exceeding the own weight of the diffusion plate occurs.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical embodiment according to the present invention will be described with reference to FIGS. In the following, the same portions are denoted by the same reference numerals, and detailed description may be omitted.

FIG. 1 is a diagram showing the principle of the mechanism of the present invention.

Referring to FIG. 1, a flat-bed type document reading apparatus capable of reading a transparent document 1 includes a main body 10 of the apparatus.
And an openable / closable document cover 2 attached to the apparatus main body. Further, the apparatus main body 10 includes a reflecting mirror 63.
And a reading unit 62 having an imaging lens 64 and a CCD 65, and travels on a reference axis 66 in the sub-scanning direction by driving a drive belt (not shown). The apparatus main body 10 also includes a document table 11 on which the transparent document 1 is placed. The above has the same form as the prior art shown in FIG.

On the other hand, the original cover 2 is movable in the Z direction with the diffuser plate 5 facing the original platen 11 in order to diffuse the light from the light source 3 and absorb the positional deviation from the reflecting mirror 63. In preparation. Further, it is preferable that the document cover 2 is configured so that the light source unit 4 having the light source 3 travels on the basis of the diffusion plate 5 by a driving element (not shown) in synchronization with the traveling of the reading unit 62.

Further, a gap 20 is formed in the engaging portion between the diffusion plate 5 and the cover frame 13 of the document cover 2. Further, the document cover 2 is provided with a pressure element 6 for pressing the diffusion plate 5 toward the document table 11.

Further, at both ends of the light source unit 4 in the main scanning direction, there are provided contact members 14 which are in contact with the diffusion plate 5 and run, for example, composed of sliding members. This light source unit 4
Is a pressing element 12 composed of a spring 15 for pressing the diffusion plate 5.
Is provided.

Hereinafter, embodiments of the present invention will be described in detail.

FIG. 2 is a diagram (part 1) of an embodiment of the present invention.

In the figure, the cover frame 13 of the document cover 2 has a U-shape, and a place where a diffuser plate is mounted;
And a place where the light source unit 54 is mounted. When the diffusion plate 5 is mounted on the cover frame 13, a gap 20 is provided between the cover frame 13 and the diffusion plate 5.

As the light source unit, a light source unit 54 having the same form as that of the prior art shown in FIG. 7 may be mounted, or the light source unit 24 shown in FIGS.
May be attached. When the light source unit 54 is mounted, the distance from the document table 11 to the light source 53 is kept constant by moving the diffusion plate 5 in the vertical direction according to the thickness of the transparent document 1.

FIG. 3 is a diagram (part 2) of the embodiment of the present invention.

In the same figure, when the diffusion plate 5 is mounted in the gap 20 shown in FIG. 2 described above, a pressing element 21 made of a spring member is provided on the upper surface of the diffusion plate 5. This pressing element 21
And presses the diffusion plate 5 toward the original table side.

FIG. 4 is a diagram (part 3) of the embodiment of the present invention.

FIG. 3 shows the detailed structure of the document cover 2. The driving element of the light source unit 24 is the document cover 2
Has a guide rail 30 extending in the sub-scanning direction, and a rack 31 is formed on one of the guide rails 30. The unit frame 29 of the light source unit 24 has the light source 23, a pulse motor 37, and gears 33 and 34. Further, it has a pinion 32 and is axially mounted so as to mesh with the rack 31. The pinion 32 is driven by a pulse motor 37 via gears 33 and 34.

Further, on the surface of the guide rail 30 opposite to the surface on which the rack is formed, slide shoes 35 provided on the light source unit 24 are resiliently pressed by a pressing element 36 at positions on both sides of the engagement position of the rack. I have. The direction of the light source unit 24 is defined by the two slide shoes 35.

On the other hand, on both sides of the unit frame 29 of the light source unit 24 in the main scanning direction, there are provided contact members 28 made of, for example, sliding members which are in contact with the diffusion plate 5. The light source unit 24 runs on the basis of the diffusion plate 5.

The diffusion plate 5 is mounted with a gap 20 so that it can move up and down with respect to the cover frame 13. In this example, the distance from the diffusion plate 5 to the light source 23 is kept constant by moving the diffusion plate 5 in the vertical direction corresponding to the thickness of the transparent original 1.

FIG. 5 is a diagram (part 4) of the embodiment of the present invention.

4, when the light source unit 24 shown in FIG. 4 is mounted on the cover frame 13, the pressing element 42 provided with a contact member 41 such as a sliding member at one end of a spring 43 is attached to the light source unit. 24 is provided at substantially the center. The light source unit 24 is pressed toward the diffusion plate 5 via the pressing element 42.

[0054]

As described above, according to the present invention, the following effects can be obtained.

In a flat-bed type document reading apparatus comprising a device body having a reading unit and a document table, and a document cover having a light source and a diffusion plate and openably and closably mounted on the device body, the document is placed on the document table. The distance between the transparent document and the light source can be changed according to the thickness of the transparent document.
Since the light source is arranged with reference to the transparent original placed on the platen, the amount of light irradiated on the transparent original is stabilized,
The amount of light received by the CCD can be stably kept constant. Therefore, the reading quality of various transparent originals can be improved.

Further, the diffusion plate can be moved in the direction of the light source. Alternatively, since the diffusion plate is engaged with the cover frame with a gap formed by the cover frame and the diffusion plate of the document cover, the diffusion plate traces the transmission document by its own weight, thereby providing a distance between the various transmission documents and the light source. Can be kept constant.

Further, since the original cover is provided with a pressing element for pressing the diffuser plate toward the original platen, the diffuser plate traces the transparent original by the external pressure. The distance between the transparent document and the light source can be kept constant.

Further, the light source unit having the light source runs while being in contact with the diffusion plate. Further, since the light source unit is provided with contact members at both ends in the main scanning direction, which contact the diffusion plate, the light source unit can be moved with reference to the diffusion plate. Accordingly, since the amount of light irradiated on the transmission original is stabilized, the amount of light received by the CCD can be stably maintained constant. Therefore, the reading quality of various transparent originals can be improved.

Further, the light source unit includes a pressing element for pressing the diffusion plate. Further, since the light source unit includes a pressing element that presses between the cover frame and the light source unit by a spring having a contact member at a substantially central portion in the main scanning direction, the light source unit travels based on the diffusion plate. be able to. At the same time, the diffusion plate traces the transparent original by the external pressure, and even if a warp exceeding the own weight of the diffusion plate occurs, the distance between the various transparent originals and the light source can be kept constant by the external pressure.

[Brief description of the drawings]

FIG. 1 is a mechanism principle diagram of the present invention.

FIG. 2 is a diagram (part 1) of an embodiment of the present invention.

FIG. 3 is a diagram (part 2) of the embodiment of the present invention.

FIG. 4 is a diagram (part 3) of the embodiment of the present invention.

FIG. 5 is a diagram (No. 4) of the embodiment of the present invention;

FIG. 6 is a schematic diagram of a conventional technique.

FIG. 7 is a structural diagram of a related art.

FIG. 8 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 1: Transparent document 2: Document cover 3: Light source 4: Light source unit 5: Diffusion plate 6: Pressing element 11: Document table 12: Pressing element 13: Cover frame 14: Contact member 15: Spring 20: Gap portion 24: Light source unit 41: contact member 42: pressing element 43: spring

Claims (8)

[Claims] 1. A flat bed type document reading apparatus comprising: a device main body having a reading unit and a document table; and a document cover having a light source and a diffusion plate and openably and closably mounted on the device body. A flat bed type document reading apparatus, wherein the distance between the placed transparent document (1) and the light source (3) can be changed according to the thickness of the transparent document (1). 2. The flatbed type document reading apparatus according to claim 1, wherein the diffusion plate (5) is movable in the direction of the light source (3). 3. The diffusion plate (5) is engaged with the cover frame (13) by a gap (20) formed by the cover frame (13) of the document cover (2) and the diffusion plate (5).
3. The flatbed type document reader according to claim 2, wherein: 4. A document cover (2) having a pressing element (6) for pressing a diffusion plate (5) toward a document table (11). 2. The flatbed type document reader according to claim 1. 5. A flat according to claim 1, wherein the light source unit (4) having the light source (3) travels in contact with the diffusion plate (5). Bed type document reader. 6. A flatbed type document reading apparatus according to claim 5, further comprising contact members (14) abutting on a diffusion plate (5) at both ends of the light source unit (4) in the main scanning direction. . 7. The flat light source according to claim 1, wherein the light source unit (4) includes a pressing element (12) for pressing the diffusion plate (5). Bed type document reader. 8. The light source unit (24) presses between the cover frame (13) and the light source unit (24) by a spring (43) having a contact member (41) at a substantially central portion in the main scanning direction. The flatbed document reader according to claim 7, comprising a pressure element (42).